Metro 100G and Beyond

The explosion of digital video, cloud access and data center traffic is driving the growth of 100 Gb/s fiber optic networks, or 100G, in metro environments. Today, 20G or 40G is sufficient for most metro networks, but "going forward, 100G will be the bandwidth of choice," said Michael Belanger, a product manager at Ciena Corporation.

Randy Nicklas, executive vice president and engineering and chief technology officer for Windstream, said his company is seeing increased demand for bandwidth, especially to residential homes. “We deliver packets to our customers in both directions in increasing scale. That's why 100G is important to us,” Nicklas said.

Speaking about the economics of building 100G networks, Ryan Yu, vice president of business development and general manager of active products at Oplink Communications, pointed out that telecom companies have traditionally been the biggest spenders on infrastructure. But due to their increasing data transmission demands, Internet companies such as Facebook, Netflix and Baidu are catching up fast and are expected to outpace telecom companies in spending in the coming years.

As the industry shifts to higher data speeds, there are many challenges that will need to be overcome. For example, Jinghui Li, president of the optical thin film filter supplier Auxora, noted that below 20G, most client-side transceivers rely only on single wavelengths, but as speeds increased to 40G and now 100G, optics technologies such as WDM become necessary for long-distance data transmission.

The fiber pigtailed WDM modules used in the first generation of 100G transceivers were bulky and expensive. The filter block and PLC-AWG WDM used in the second generation 100G transceivers were smaller and less expensive and will still be used for years to come, Li said. Third-generation 100G transceivers that use silicon photonics WDM modules will soon be on the market, but details about their performance and costs are still unknown. Li predicted that depending on the application, filter block, PLC-AWG, and silicon photonics WDMs could co-exist.

Mike Capuano, vice president of marketing at Infinera, said that as data speeds increase, new network models will need to be created that are capable of tailoring the bandwidth to particular needs. For example, a 400G line could be reserved for a node in the network that only needs 80G. "As the industry moves to 100G to 200G to 400G in the metro, there's a lot of potential to waste a lot of bandwidth," Capuano said. "As an industry, we want to figure out how to get maximum capacity but also get the right amount of granularity to feed the system at the appropriate rate."